My son really likes this Lego set and you get a lot for your money. Firstly, the Hagrid figure is fantastic. He is much taller than the others and comes complete with his pink umbrella. There is also a light brick for the fire, so with the push of a small switch there is a blazing fire in the hut. The hut can be folded or opened up to play inside. It is also the cheapest set to feature Harry, Ron and Hermione.
The build was generally straight forward. The hinging required some parental engineering help, but my six year old got on quite well. He shared the build with his Mum, and apart from a few bricks where the colour had to be examined properly (the greys and blacks in the instructions can look the same), but generally did quite well with it. The Aragog is rather good and my son supplemented the spider army with some others from other sets to create a great enemy for the wizards to battle.
This would be a great set to start a Lego Harry Potter collection as you get the three principal characters, Hagrid, a fearsome enemy in Aragog and a great building. That makes it excellent value for money.